Cadmium Selenium Zinc Sulfur Silica Core Shell (CdSe/ ZnS/SiO2, 99.9%, APS: 80-100nm, Metal Salt Core)

Cadmium Selenium Zinc Sulfur Silica Core-Shell Nanoparticles

Cadmium Selenium Zinc Sulfur Silica Core-Shell nanoparticles with their unique size-dependent properties, have drawn significant attention in various scientific fields, including materials science, medicine, electronics, and catalysis. Among the diverse types of nanoparticles, core-shell structures—where one material (the core) is surrounded by a different material (the shell)—are particularly interesting due to their enhanced properties, which arise from the interaction between the core and shell materials. In this context, cadmium-selenium-zinc-sulfur-silica core-shell nanoparticles represent a cutting-edge class of nanomaterials that integrate the distinctive properties of semiconducting materials with the stability and versatility of silica coatings.

Core Composition: CdSe and ZnS

Cadmium Selenide (CdSe): CdSe is a widely studied semiconductor material known for its strong photoluminescent properties. It exhibits efficient light absorption and emission, making it a popular choice for applications in optoelectronics, such as light-emitting diodes (LEDs), solar cells, and biological imaging. However, CdSe has limitations due to its toxicity, which is a significant challenge when considering its use in biomedicine and other applications requiring biocompatibility.

Zinc Sulfide (ZnS): ZnS is often used as a passivating layer on CdSe cores because it has a wide bandgap and excellent optical transparency. The ZnS shell helps to improve the photostability and prevent photo-induced degradation of CdSe. The inclusion of ZnS also enhances the overall quantum yield and performance of the nanoparticles in optoelectronic applications.

Together, the combination of CdSe and ZnS in the core of the nanoparticle allows for superior optical properties, including tunable fluorescence and high quantum efficiency. The structure also provides a means to manipulate the band gap and photoluminescent properties by adjusting the core composition and the thickness of the ZnS shell.

Silica Shell: Stability, Functionalization, and Biocompatibility

The silica shell surrounding the CdSe-ZnS core adds another layer of functionality and protection. Silica (SiO₂) is a biologically compatible and chemically stable material, which provides several advantages:

Stabilization: The silica shell serves as a protective layer that prevents the core from undergoing degradation due to environmental factors, such as exposure to oxygen, moisture, or acids. This protection is critical for maintaining the long-term stability and performance of the nanoparticles, especially in harsh environments.

Functionalization: Silica surfaces are rich in silanol (Si-OH) groups, which can be easily functionalized with a variety of molecules, such as targeting ligands, antibodies, or other bioactive agents. This makes silica-coated nanoparticles ideal for use in targeted drug delivery, biosensing, and imaging applications.

Biocompatibility: Silica is non-toxic and biocompatible, making silica-coated nanoparticles suitable for biomedical applications, including in vivo imaging, drug delivery, and therapeutic interventions. The biocompatibility of silica also reduces the potential risks associated with the use of toxic core materials like CdSe.

Controlled Release: The silica shell can be engineered to allow for the controlled release of encapsulated drugs or other biomolecules, which is a valuable feature in therapeutic applications.